Windows Update Stack Elevation of Privilege Vulnerability
CVE-2026-81963
Scope
What the vendor says is affected
- Windows Server 2025 (Server Core installation)
- Windows 11 Version 25H2 for ARM64-based Systems
- Windows 11 Version 25H2 for x64-based Systems
- Windows 11 Version 24H2 for ARM64-based Systems
- Windows 11 Version 24H2 for x64-based Systems
- Windows Server 2025
- Windows 11 version 26H1 for x64-based Systems
- Windows 11 Version 26H1 for ARM64-based Systems
Versions the vendor lists as fixed
- 10.0.26100.33296
- 10.0.26100.33222
- 10.0.26200.9168
- 10.0.26200.9106
- 10.0.26100.9168
- 10.0.26100.9106
- 10.0.28000.2704
Next step
What the vendor recommends
Install KB5120233. Install KB5120228. Install KB5121003. Install KB5120994. Install KB5121000.
Review the complete instructions on the vendor's siteUpdate history
What changed in later vendor updates
SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.
- The vendor changed its remediation guidance.
Timeline
When this advisory changed
- Published by Microsoft Security Response Center
The publication date reported by the vendor.
- Added to SecurityAlert
We collected the advisory from the official source.
- Confirmed at the source
Our collector saw this advisory during a later source check.
Vulnerabilities